Various types of boat lifts have heretofore been devised to elevate boats out of the water for storage or to permit the hull to be checked or worked on. The most successful type of boat lift heretofore devised for pleasure size boats has been the side loading boat lift wherein a plurality of angularly extending rails project into the water at an angle and boat carriers slideably movable on the rails have horizontal extensions to project under the boat and the boat is supported in an upright position thereon. A plurality of masts secured in suitable foundations support the rails, and the boat is pulled up the rails. In units heretofore devised the cables extended over the top of the rails and are connected directly to the boat carriers slidably mounted on the rails. These constructions have been very dangerous because in the event of the breakage of a cable as occasionally happens, the cable being under considerable tension will fly and seriously injure anyone in the area. This has constituted a very serious problem in the development of commercially acceptable boat lifts.